Making oxids of bismuth



snares PATENT onnrcn.

CARLETON ELLIS, OF MON TCLAIR, NEW' JERSEY, ASSIGNOR T0 ELLIS FOSTER GOMPAN Y, A CORPORATION OF NEW JERSEY.

MAKING OXIDS 0F BISMU'I'H.

No Drawing.

To all whom it may concern Be it known that I, CARLETON ELLIS, a citizen of the United States, and a resident of Montclair, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Making Oxids of Bismuth, of which the following is a specificati0n.

This invention relates to a method of making oxids of bismuth and is concerned especially with the oxidation of the finely divided metal by combustion in air or oxygen or in an oxidizing atmosphere of regulated oxidizing power, and relates especially to such ignition, combustion, or oxidation of bismuth which may be prepared in a powdered form by pulverizing or by comminution of the molten metal, all as will be hereinafter described.

Metallic bismuth may be pulverized quite readily to a fine powder by grinding as for example by treatment in a ball mill or other grinding apparatus. The molten metal also may be comminuted by directing a powerful blast of air or inert gas, products of combustion under pressure, or steam, either Wet steam or superheated steam, whereby the metal may be obtained in the form of a powder or in a filamentous condition. Obtained in these or other suitable ways, the bismuth may be burned in an oxidizing atmosphere to the oxid, such for example as the yellow or lower oxid without any substantial degree of coalescence, thereby precluding the formation of large globules of the metal which would not readily oxidize. The invention will be illustrated by the following procedures.

The simplest form of the oxidation proc ess is that of grinding the bismuth metal to a fine powder, say one Which will pass a 1.00 mesh screen and allow this, powder to fall through the flame of a powerful Bunsen burner; combustion takes place and great quantities of yellow smoke or fume are produced which when coming in contact with a cold surface yield a yellow sublimate and the portion of the fume which is so de .osited be collected b means of bag .lters in any ether suitab e manner. Any

Specification of Letters Patent.

Patented Oct. 7, 1919.

Application filed January 4, 1919. Serial No. 269,665.

particles of bismuth which may be too coarse or which through defective exposure have not had opportunity to become ignited will collect in the neighborhood of the base of the lamp and may be recovered. By this operation the particles of the bismuth are kept apart a sufiiciently long time while being heated so that they burn as separate particles and combustion takes place quite readily throughout the mass of the particles to yield a satisfactory oxidation product.

Another manner of carrying out the process is by injecting the powdered bismuth into the air of an ordinary blast lamp burnmg gas, oil or any other suitable fuel so that the powdered metal is projected with the air or gas current into a zone in which intense combustion is progressing, whereupon oxidation may thus take place without coalescence and the fumes collected as indicated above.

In a similar manner the metal prepared by directing a powerful jet of air, steam, inert gas or gas of regulated oxygen content upon a stream of the molten metal may 'be employed in the foregoing operations or the comminution of the metal may take place simultaneously with its oxidation. For example the powder of metal coming from the jet may pass directly into a flame where it is burned; or the molten metal may be comminuted by a jet of air and gas coming from a blast lamp so that as the metal is comminuted it is subjected to an igniting temperature and while the particles of the molten metal are being torn apart they are at the same time ignited and burned to the oxid. By using a series of dust chambers and bag filters different grades of the product may be obtained. The heaviest portion containing the larger particles may be too impure for use and may be re-melted and again atomized.

In place of bismuth its alloys or ores adapted for the purpose or other analogous raw materials may be employed.

What I claim is 1. The process of making bismuth oxid which comprises projectin comminuted bismuth into flame y the bismuth is burned to the oXicl and in collecting the bismuth products resulting from such oxida- Mon.

2. The process of making, bismuth. oxid Which; comprises injecting pulverized bismuth into a heated zone whereby ignition of the bismuth takes place.

3. The'process of making an oxid of bismuth Which comprises passing 'comminutedbismuth into a heated zone in suchamanner Copies of this patent may be obtained for that the particles of the bismuth are kept from coalescing and in permitting the particles to oxidize in said zone.

4:. The process of making bismuth oxid which comprises projecting comminuted bismuth into a blast flame.

5. The process of making bismuth oxicl which comprises melting the metal and at0- mizing-the molten metal in a blast flame.

CARLETON ELLIS.

five cents each, by addressing the Commissioner of Patents.

Washington; D; 0: 

